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Background. . Shapes of the recovery unit: mop, belt, brush, disc, and drum. Materials of the recovery surface: steel, aluminum, and general-use plastics (polyethylene and polypropylene)Material selection has not been based on the adhesive properties, but rather on historical practice, price and availability. .
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1. A Method to Characterize Materials to be Used on Oleophilic Skimmers Victoria Broje and Dr. Arturo A. Keller
Bren School of Environmental
Science and Management, UC Santa Barbara
IOSC 2005, Florida
2. Background Shapes of the recovery unit: mop, belt, brush, disc, and drum.
Materials of the recovery surface: steel, aluminum, and general-use plastics (polyethylene and polypropylene)
Material selection has not been based on the adhesive properties, but rather on historical practice, price and availability.
3. Objective To study the dependence of oil adhesion to various recovery surfaces on:
Physicochemical properties of the polymeric material
Roughness of the material
Geometry / pattern of the recovery surface
Oil and oil emulsion properties:
viscosity, density, SARA composition, weathering degree, water content
Contact time (withdrawal rate)
Temperature
4. Expected Results The proposed research will help identifying parameters having major effect on oil adhesion to the recovery surface.
Material (or a group of materials) that has the highest oil recovery rate will be selected.
We will provide analysis showing how using new materials and surface patterns can help increasing efficiency of mechanical oil spill cleanup equipment.
5. Previous Research Jokuty, P., Whiticar, S., McRoberts, K., Mullin, J.,
Oil adhesion testing – recent results. 1996.
Liukkonen S., Koskivaara R., Rytkonen, J., Lampela, K., Adhesion of oil to plastics, stainless steel and ice. 1995.
6. Contact Angle
7. Dynamic Contact Angle Analyzer
8. Test Oils
9. Test Materials - Screening
10. Test Materials - Further tests
11. Preliminary Results - Plastics
12. Preliminary Results - Elastomers
13. Previously-oiled surfaces
14. Effect of Roughness
15. Effect of Roughness
16. Pattern of the Recovery Device Ways to use surface pattern for increasing recovery efficiency:
Increase oil film thickness
By angle of withdrawal
By using capillary forces
Increase contact area
The difficulties:
Scraping oil off the brush
Oil properties are changing
17. Proposed Surface Pattern
18. Proposed Surface Pattern Advantages:
Changes involve only recovery unit. No changes required for skimmer frame;
Increases surface area up to 4 times;
Increase oil film thickness by using capillary forces and forming a meniscus;
Can be used on drums and belts. Belt configuration will ensure lower withdrawal angle and thicker oil film formation;
Applicable for various oil properties;
Scraper can remove close to 100% of recovered oil.
Full-scale test is needed to provide information on the efficiency of such configuration for real life spills.
19. Conclusions Contact angle and contact angle hysteresis can provide valuable information about the affinity of various materials to oil, and allow comparison between them.
Elastomers were identified as candidates for better recovery surfaces.
Surface roughness and oil composition have a significant effect on the adhesion.
Surface pattern has potential to increase oil recovery efficiency.
20. Future Experiments Adhesion in presence of water
Effect of oil emulsion formation on adhesion
Effect of material roughness
Effect of test surface shape and pattern
Effect of temperature
Optimum contact time between oil and recovery surface (optimal withdrawal speed)
Full-scale oil spill recovery test at Ohmsett to verify these results
21. Acknowledgements This work was co-funded by
United States Department of the Interior, Mineral Management Service
and
University of California Toxic Substances Research and Teaching Program.
22. Questions ?